1. Field of the Disclosure
The present application relates to an organic light emitting diode display device. More particularly, the present application relates to an organic light emitting diode display device adapted to block an intrusion path of external moisture and to a method of fabricating the same.
2. Description of the Related Art
The organic light emitting diode devices are self-illuminating display devices. As such, the organic light emitting diode devices do not need any separate light source, unlike a liquid crystal display device. In accordance therewith, the organic light emitting diode display devices can become lighter and thinner. Also, organic light emitting diode display devices have the features of wider viewing angle, superior contrast, and lower power consumption than those of liquid crystal display devices. Moreover, organic light emitting diode display devices can be driven by a low direct-current voltage and provide a high speed response. Furthermore, organic light emitting diode display devices can well resist external impacts and be used in a wide temperature range because of having solid components.
In organic light emitting diode display devices, external oxygen and moisture may cause damage on some electrodes. External oxygen and moisture may deteriorate a lifespan of organic light emitting diode display devices. Therefore, it is very important to package an organic light emitting element and avoid exposure to external oxygen and moisture.
As a packaging method, an entire surface sealing process can be used in organic light emitting diode display devices. In the entire surface sealing process, an element substrate provided with organic light emitting diodes can be bonded to a sealing substrate by means of a sealant which is formed on the entire surfaces of the element substrate and the sealing substrate. The conventional basic structure of organic light emitting diode display devices will now be described referring to FIGS. 1 and 2.
FIG. 1 is a planar view showing an organic light emitting diode display device of the related art. Referring to FIG. 1, organic light emitting diodes 20 are formed on an element substrate 10. Each of the organic light emitting diodes 20 can include a first electrode, an organic layer configured to include at least a light emission layer, and a second electrode. Moreover, thin film transistors (not shown) each include a semiconductor layer, a gate electrode, a source electrode and a drain electrode can be formed on the element substrate 10. Subsequently, a sealing layer can be formed between the element substrate 10 and a sealing substrate 18. The element substrate 10 and the sealing substrate 18 can be bonded by means of the sealing layer. The sealing layer can include a second passivation layer and an adhesive layer. Such an organic light emitting diode display device can be described referring to a cross-sectional view which shows an edge portion “A” of the substrates 10 and 18.
FIG. 2 is a cross-sectional view showing an organic light emitting diode display device of the related art. As shown in FIG. 2, a first passivation layer 11 is formed on the element substrate 10. The first passivation layer 11 is used to protect thin film transistors, among others. Also, first electrodes 12 of the organic light emitting diodes are formed on the first passivation layer 11. Moreover, an insulation film 13 defining emission regions is formed on the first passivation layer 11. The emission regions expose the first electrodes 12. Further, an organic layer 14, which is configured to include an emission layer, and a second electrode 15 are applied on the insulation film 13 and the exposed first electrodes 12. The first electrode 12, the insulation film 13, the organic layer 14 and the second electrode 15 form an organic light emitting diode. Furthermore, a second passivation layer 16 is formed on the organic light emitting diodes, particularly on the second electrode 15. The second passivation 16 is formed in such a manner as to encompass the elements on the element substrate 10 to protect the elements on the element substrate 10 against, for example, moisture, gas. Finally, an adhesive layer 17 is formed on the exposed surfaces of the second passivation layer 16. The sealing substrate 18 is bonded to the element substrate 10 by means of the adhesive layer 17, thereby completing an organic light emitting diode display device.
FIG. 14A illustrates an experimental resultant for a rolling phenomenon which is generated in an organic light emitting diode display device of the related art including the device as shown in FIG. 2.
Referring to FIGS. 2 and 14A, the organic light emitting diode has a weak interfacial adhesion force between the insulation film 13 and the first passivation layer 11. As such, the insulation film 13 can roll up. The rolling of the insulation film 13 causes a portion of the second passivation layer 16 to separate from a side surface of the insulation film 13, thereby generating cracks as shown in FIG. 14A. As such, the cracks generated in the second passivation layer 16 may serve as intrusion paths for external moisture, gas, among others.